A five-year longitudinal study of the development of acne in children will be carried out by examination of its relationship to sebaceous gland secretion (sebum), urine steroid excretion (total 17-ketosteroids and testosterone) and pubertal development. Sebaceous gland activity will be assessed by two methods; surface lipid composition and gravimetric assay. The purpose of this investigation is two-fold: (a) to determine the possible role of androgens and sebum in the initiation, maintenance and progression of the disease acne; and (b) to identify retrospectively children at greater risk for the ultimate development of significant clinical involvement with acne by the analysis at an earlier age of the various factors to be examined. Androgen metabolism of the skin and sebaceous gland tissue will also be studied, by in vitro examination of the transformation of testosterone in these tissues, with study of the factors that affect these conversions. Once these have been identified, investigation will be carried out on the effect of 5 gamma-reductase inhibitors on human sebaceous glands in vitro; if successful, these would be of potential benefit in the treatment of acne.